Despite the increased automation of large-scale package handling systems, most such systems continue to have one or more steps performed manually, i.e., involving human operators handling the packages. In particular, prior to entering a sorting system packages are typically unloaded from vehicles onto a conveyor. The conveyor transports the packages to one or more slides, which are typically divided into multiple lanes. Diverter arms typically control which slide and lane packages will be diverted to at any given time. Human operators typically man individual lanes by moving the packages from the slide lanes to the sorting system. Multiple lanes are provided to distribute the delivery of the packages from the slide(s) to the sorting system among the available operators.
Typically, control of the diverter arms is based on a timing algorithm that changes the active lane at fixed predetermined intervals. Unfortunately, such a system does not always properly allocate packages to the available lanes. If the operators fail to clear a lane at the pace defined by the predetermined timing algorithm, the lane may become overfull causing possible damage to the packages and possible disruption of the automated portions of the package flow. Accordingly, there is a need for improved systems for monitoring package flow on slides.